Antibiotic pollution has become one of the most important emerging soil contamination types, and has received great attentions
in recent years. Understanding the microbial functional processes of soil ecosystems under antibiotic contamination is of critical
importance for ecological risk assessment and pollution control. In this study, the responses of soil microbial respiratory activity
and ammonification were studied under different concentrations of tetracycline, chlortetracycline, and norfloxacin. Generally, the
antibiotic residuals showed a depressed effect on microbial respiration with residual concentrations of 1-20 ppm, and the effect
was dose- and type - dependent. Depression was apparent at high doses. Stimulation effects were only occasionally observed at
low concentrations. Similar results were also observed in ammonification with the maximal inhibition rate exceeding 8%. The
depression effect on ammonification was gradually weakened in two weeks. Soil microbial cellulose decomposition activity was
studied with the addition of tetracycline, chlortetracycline, norfloxacin, and enrofloxacin. The four types of antibiotics were
tested separately under the same concentration (10 ppm). The cellulose decomposition rates with treatments of tetracycline,
chlortetracycline, enrofloxacin and norfloxacin were 5.2%, 4.9%, 4.8%, and 4.5%, respectively, which were lower than the
control (5.5%).